Hold open rods are well known in the both the automotive industry and the aviation industry. Hold open rods hold open a door or hatch after the door or hatch has been opened manually or automatically. Hold open rods may support a considerable amount of weight. It is desired that the rods function correctly and do not malfunction in supporting this weight.
Generally, the rods include two cylindrical, telescoping tubes, a first tube disposed inside a second tube, this constitutes an inner and outer tube, respectively. When in the resting or “stowed” position, the inner tube is generally located almost entirely within the outer tube. The inner tube can be extended to a designated position to hold open the door. At this extended position, the tubes are locked in place, in order to open the door. Such locking prevents the inner tube from retracting into the outer tube and also permits the tubes to support the weight of the door. The locking mechanism can be released by an operator.
In aerospace applications hold open rods are often subject into intense vibration during flight. Due to the interaction between the inner tube and the outer tube, unwanted noise and fretting occurs between contacting parts. This fretting can cause premature wear to the hold open assembly. Further, the fretting may potentially damage or eliminate the corrosion protection coating applied to components of the hold open rod and thereby potentially compromise the ability of the hold open rod to be resistant to corrosion. Removing corrosion resistant coatings may potentially impair the functionality of the hold open rod.
Thus it would be desirable for a method or system that can dampen or eliminate noise and fretting between hold open rod components. Particularly, dampening is desired in hold open rods used in the aviation industry. In the aviation industry, a door or hatch is likely to be maintained in the closed position where vibration may be experienced between the various components of the hold open rod, and where significant fretting has long been known to occur. Further, it may be desirable for the dampening system to reduce noise and/or wear due to vibration of the hold open rod.